BUG: Series.apply() throws an error on empty series when dtype = pd.StringDtype

[IDDT]

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• (optional) I have confirmed this bug exists on the master branch of pandas.

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Code Sample, a copy-pastable example

pd.Series(['a', 'b', 'c']).iloc[0:0].apply(lambda x: x) #works as expected
pd.Series(['a', 'b', 'c']).astype('string').iloc[0:0].apply(lambda x: x) #throws an exception

Problem description

Applying a function to an empty Series with dtype pd.StringDtype throws ValueError: PandasArray must be 1-dimensional..

Expected Output

Apply does nothing.

Output of pd.show_versions()

INSTALLED VERSIONS

commit : None
python : 3.8.1.final.0
python-bits : 64
OS : Linux
OS-release : 5.6.3-arch1-1
machine : x86_64
processor :
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8

pandas : 1.0.3
numpy : 1.18.2
pytz : 2019.3
dateutil : 2.8.1
pip : 20.0.2
setuptools : 41.2.0
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : 2.8.5 (dt dec pq3 ext lo64)
jinja2 : 2.11.2
IPython : 7.13.0
pandas_datareader: None
bs4 : None
bottleneck : None
fastparquet : None
gcsfs : None
lxml.etree : None
matplotlib : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pytables : None
pytest : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
xlsxwriter : None
numba : None

[TomAugspurger]

Thanks for the report. Slightly smaller reproducer

pd.Series(dtype="string", index=[])

We try to insert np.array(<NA>).

In _init_dict

    354         elif index is not None:
    355             # fastpath for Series(data=None). Just use broadcasting a scalar
    356             # instead of reindexing.
    357             values = na_value_for_dtype(dtype)
    358             keys = index

I'm not sure if that would need to change (special case length-0?) or whether create_series_with_explicit_dtype should change.